Low Electrical Resistivity of Nano WO3-doped ZnO Thermoelectric Material

Abstract

The ZnO thermoelectric material was reduced electrical resistivity by doping nano WO₃ powder in solid-state reaction process by using ZEM-3 at temperature range of 373 – 873 K in Ar atmosphere. The results found that the XRD patterns show the nebulous phase matches with of ZnWO₄ belonging to the monoclinic structure. In XRD patterns were appeared WO₃ peaks in crystalline structure of ZnWO₄ phases, and the SEM showed an intensive distribution of WO₃ into the grain boundaries. The average Seebeck coefficient of WO₃-doped ZnO sample was increased from −30 to −75 μV K⁻¹ indicate n-type thermoelectric materials. Moreover, we can reduce the electrical resistivity ranged from 16 mW cm to 34 mW cm. The highest power factor of sample is 0.024 mW m⁻¹ K⁻² at 473 K. The results revealed that doping nano WO₃ with ZnO also could promote to using for the thermoelectric devices at high temperature application.